Spinal near-infrared spectroscopy measurements during and after thoracoabdominal aortic aneurysm repair: a pilot study.

BACKGROUND: Near-infrared spectroscopy (NIRS) is a noninvasive technique that allows continuous monitoring of regional hemoglobin oxygen saturation (rSo2). We evaluated its application to survey oxygenation of the spinal cord region during open thoracoabdominal aortic aneurysm (TAAA) repair and postoperatively in the intensive care unit (ICU). We also validated its association with motor-evoked potential (MEP) monitoring during the operation. METHODS: The rSo2 curves of 15 patients (8 men; mean age, 64.2 ± 7.7 years) were measured continuously with NIRS at spinal cord levels of the thoracic vertebrae T3 (optode 1, reference spot) and T12 (optode 2) during open TAAA repair. T12/T3 ratios were calculated. NIRS measurements were continued in the intensive care unit and stopped 24 hours after the operation. MEP monitoring was performed in all patients during the procedure. RESULTS: No clinical signs of spinal cord ischemia were documented in any of the patients. Continuous NIRS measurements were successfully performed in all patients during and after the operation. T12/T3 ratios were significantly lower in the MEP ratios that were less than 50% compared with the MEP ratios that were 50% or higher (p = 0.037). CONCLUSIONS: NIRS is an easily applicable noninvasive tool for continuous surveillance of oxygenation of the spinal cord region during TAAA repair and postoperatively in the intensive care unit. The rSo2 curves provide useful information concerning hemodynamic changes in oxygenation of the spinal cord region and might contribute to early detection of spinal cord ischemia. Further investigation is needed before broad clinical implementation.

Comparison of Warm Blood Cardioplegia Delivery With or Without the Use of a Roller Pump.

Various techniques for administration of blood cardioplegia are used worldwide. In this study, the effect of warm blood cardioplegia administration with or without the use of a roller pump on perioperative myocardial injury was studied in patients undergoing coronary artery bypass grafting using minimal extra-corporeal circuits (MECCs). Sixty-eight patients undergoing elective coronary bypass surgery with an MECC system were consecutively enrolled and randomized into a pumpless group (PL group: blood cardioplegia administration without roller pump) or roller pump group (RP group: blood cardioplegia administration with roller pump). No statistically significant differences were found between the PL group and RP group regarding release of cardiac biomarkers. Maximum postoperative biomarker values reached at T1 (after arrival intensive care unit) for heart-type fatty acid binding protein (2.7 [1.5; 6.0] ng/mL PL group vs. 3.2 [1.6; 6.3] ng/mL RP group, p = .63) and at T3 (first postoperative day) for troponin T high-sensitive (22.0 [14.5; 29.3] ng/L PL group vs. 21.1 [15.3; 31.6] ng/L RP group, p = .91), N-terminal pro-brain natriuretic peptide (2.1 [1.7; 2.9] ng/mL PL group vs. 2.6 [1.6; 3.6] ng/mL RP group, p = .48), and C-reactive protein (138 [106; 175] µg/mL PL group vs. 129 [105; 161] µg/mL RP group, p = .65). Besides this, blood cardioplegia flow, blood cardioplegia line pressure, and aortic root pressure during blood cardioplegia administration were similar between the two groups. Administration of warm blood cardioplegia with or without the use of a roller pump results in similar clinically acceptable myocardial protection.

Impact of different surgical strategies on perioperative protein S100ß release in elderly patients undergoing coronary artery bypass grafting.

OBJECTIVE: This study was designed to compare neurological injury-associated protein S100ß release during three different treatment modalities, minimized closed circuit coronary artery bypass grafting (CABG) (MCABG), off-pump CABG (OPCAB), and conventional CABG (CCABG), comprising high-volume prime and cold crystalloid cardioplegia. Our working hypothesis was that fluid restriction as provided by MCABG may decrease neurological injury-associated protein S100ß release. METHODS: In this prospective trial, in a tertiary center, 30 surgical patients (aged >70 years, 25 men and 5 women) undergoing first-time elective CABG were enrolled. The inclusion criteria were three-vessel disease and elective surgery. The exclusion criteria were left ventricular ejection fraction of less than 30%, use of clopidogrel, carotid disease, or needing fewer than three distal anastomoses. Protein S100ß concentrations, hematocrit (Ht) levels, and PO2 levels were measured after induction of anesthesia, 10 minutes after reperfusion, upon arrival at the intensive care unit, 3 hours postoperatively at the intensive care unit, and the next morning. Statistics consisted of areas under the curve, peak levels, and correlation and variance tests. RESULTS: A significant negative correlation was found indicating higher S100ß release at lower Ht levels and at lower PO2 levels in all study groups. The lowest S100ß variance was measured during MCABG (Wilks Λ P = 0.052). The perioperative Ht was significantly higher in the MCABG group and in the OPCAB group compared with the CCABG group (P = 0.04 vs P < 0.01). At all time points, the S100ß protein concentration showed no significant differences between the different surgical techniques. The mean (95% confidence interval) values of S100 area under the curve were the following: CCABG, 2.3 (1.06-3.5); MCABG, 1.44 (0.6-2.21); and OPCAB, 1.87 (1.5-2.19) [independent nonparametric Kruskal-Wallis test (P = 0.13)]. The mean (95% confidence interval) peak S100 values (calculated as the maximum value seen in a patient during the research period) were the following: CCABG, 1.07 (0.4-1.68); MCABG, 0.59 (0.28-0.90); and OPCAB, 0.83 (0.59-1.06) [independent nonparametric Kruskal-Wallis test (P = 0.22)]. CONCLUSIONS: Despite similar perioperative S100ß protein release for all techniques studied, higher Ht and PO2 levels correlated with lower S100ß release within all study groups. The low S100ß variance during the fluid restrictive MCABG technique may be due to more efficient oxygen transport to the brain provided by significantly higher perioperative Ht levels. Further prospective data are required to better understand this complex issue.

J-shaped versus median sternotomy for aortic valve replacement with minimal extracorporeal circuit.

OBJECTIVES: Minimal access aortic valve replacement (AVR) has been demonstrated to have beneficial effects over median sternotomy. Minimal extracorporeal circulation (MECC) has been shown to have less deleterious effects than conventional cardiopulmonary bypass. We describe for the first time AVR via upper J-shaped partial sternotomy compared to median sternotomy using MECC. METHODS: Prospectively collected pre-operative, intra-operative, post-operative and follow-up data from 104 consecutive patients who underwent minimal access AVR were compared to 72 consecutive patients undergoing median sternotomy using MECC during the same period (January 2007 to December 2009). RESULTS: No significant differences were found in patient's characteristics or intra-operative data with the exception of pre-existing pulmonary disease. The mean cardiopulmonary bypass (86 ± 18 min vs. 78 ± 15 min, p = 0.0079) and cross-clamp times (65 ± 13 min vs. 59 ± 12 min, p = 0.0013) were significantly shorter in the median sternotomy group. Mediastinal blood loss (397 ± 257 ml vs. 614 ± 339 ml, p < 0.0001) and ventilation time (8 ± 6.9 h vs. 11 ± 16.5 h, p = 0.0054) were significantly less in the minimal access group. No differences were seen in transfusion requirements, inotropic support, intensive care unit (ICU) stay, total hospital stay, post-operative haemoglobin drop, major events or mortality. Quality of life scores after discharge demonstrated less pain with a quicker recovery and return to daily activities in patients receiving J-shaped sternotomy. CONCLUSIONS: Minimal access AVR using MECC is feasible and provides excellent clinical results. Less pain and quicker recovery was experienced among patients in this group.

Combined coronary artery bypass grafting and aortic valve replacement with minimal extracorporeal closed circuit circulation versus standard cardiopulmonary bypass.

Isolated aortic valve replacement (AVR) or coronary artery bypass grafting (CABG) using minimized extracorporeal circulation (MECC) has been shown to have less deleterious effects than standard cardiopulmonary bypass (CPB). In this prospective cohort study, we evaluated and compared clinical results of combined AVR with CABG using MECC. We prospectively collected preoperative, intraoperative, postoperative and follow-up data of 65 patients who underwent combined AVR with CABG using MECC and compared these with 135 patients undergoing combined AVR with CABG using standard CPB. No significant differences were seen in patients demographic characteristics or intraoperative data. Patients in the MECC group experienced a smaller preoperative haemoglobin drop (4.5±0.8 g/dl vs. 5.0±0.5 g/dl, P=0.002) resulting in higher haemoglobin at discharge (11.3±1.3 g/dl vs. 10.8±1.1 g/dl, P=0.03). They had decreased blood products requirements (P=0.004) compared to patients in the standard CPB group. No differences were noted in pulmonary complications, neurological events or mortality. We present for the first time data showing that combined AVR with CABG using MECC is feasible and provides better clinical results compared to standard CPB with regard to blood products requirements, without compromising operative morbidity or mortality.

Myocardial oxidative stress, and cell injury comparing three different techniques for coronary artery bypass grafting.

OBJECTIVE: Oxidative stress as a result of reperfusion injury is a known causative factor of cardiac muscle injury. In the peripheral blood as well in the coronary sinus, oxidative stress parameters and cardiac biomarkers were measured to investigate the different levels of oxidative stress during three different CABG techniques; MCABG (with minimal prime volume and warm blood cardioplegia) that was newly introduced in our hospital, versus OPCAB, versus our current standard, conventional CABG (CCABG, consisting of high volume prime and cold crystalloid cardioplegia). Concomitantly, cardiac biomarkers were measured to detect myocardial cell injury. METHODS: Thirty patients scheduled for CABG with the intention to treat three-vessel disease were randomly assigned for CCABG, MCABG or OPCAB. Perioperatively, plasma levels of malondialdehyde (MDA) as a marker of oxidative stress, and the allantoin/uric acid ratio (A/U ratio) as a marker of antioxidant activity were measured in the ascending aorta (Aa), and in the coronary sinus (Cs), simultaneously. Additionally peripheral (Aa) blood levels of heart fatty acid binding protein (HFABP), troponin T, CPK and CKMB as markers of myocardial injury were obtained. RESULTS: The MCABG group had significantly lower MDA levels in the Cs compared to the CCABG group, respectively, to the OPCAB group (p=0.04 and p=0.03). At all time points the A/U ratio in the CCABG group remained significantly higher in the Cs as well in the Aa samples compared to the MCABG and the OPCAB group (p<0.001, respectively, p<0.001, for both groups). HFABP and troponin T showed consistent curves compared to the CPK figure over time in all groups. CONCLUSION: In this study coronary sinus blood levels of oxidative stress parameters were consistently higher compared to peripheral blood levels. The levels were lowest in the MCABG study group. In this group also the lowest levels cardiac biomarkers of myocardial injury were found.

Long-term results after 27 years of surgical treatment of acute type a aortic dissection.

BACKGROUND: This study investigates the determinants of long-term outcome and modalities of late death after surgical treatment of acute type A dissection. METHODS: Between 1974 and 2001, 315 consecutive patients were operated on for acute type A aortic dissection. Operative mortality was 22.9%. A series of 243 survivors of surgical treatment were followed up for as long as 27 years. Endpoints were death, cardiovascular reoperation, and neurologic events. Median follow-up was 4.5 years. Follow-up was 99.6% complete. RESULTS: Cumulative survival of discharged patients was 96.4% +/- 1.3%, 67.7% +/- 4.7%, and 39.4% +/- 12.0% at 1, 10, and 20 years, respectively. During follow-up, 47 patients died. Cause of death was cardiac failure in 7, hemorrhage due to rupture of the distal aorta in 7, stroke in 4, respiratory insufficiency in 4, sepsis in 3, malignancy in 2, and unknown in 20 patients. Multivariate analysis revealed advanced patient age and postoperative hemodialysis as perioperative indicators of late death (p < 0.05). Freedom from cardiovascular reoperation was 90.7% +/- 2.0% at 1 year, 60.9% +/- 5.1% at 10 years and 41.9% +/- 15.0% at 20 years. A total of 58 patients required 86 cardiovascular reoperations; aortic root or ascending aorta replacement was performed in 20, distal ascending aorta and arch replacement in 13, descending aorta replacement in 6, thoracoabdominal aorta replacement in 7, abdominal aorta replacement in 7, and miscellaneous reoperations in 6 patients. Multivariate analysis revealed male sex and left coronary artery dissection as significant determinants for late cardiovascular reintervention (p < 0.05). Cumulative incidence of stroke after 20 years was 3.8%. CONCLUSIONS: Acute type A dissection represents an emergency situation with acceptable long-term results for discharged survivors of surgical treatment.

Is extended arch replacement for acute type a aortic dissection an additional risk factor for mortality?

BACKGROUND: We report our experience with surgery for acute type A aortic dissection with involvement of the aortic arch. METHODS: From January 1986 to December 2001, 277 patients underwent surgery for acute type A aortic dissection. In 70 patients (25.3%), surgery was extended into the aortic arch: hemiarch and total arch replacement in 53 (75.7%) and 17 (24.3%) patients, respectively. Deep hypothermic circulatory arrest was used in 19 patients, antegrade selective cerebral perfusion in 38, and combined deep hypothermic circulatory arrest with antegrade selective cerebral perfusion in 13. RESULTS: Operative mortality was 18.6% (13/70) after extended replacement into the arch versus 21.7% (45/207) after surgery limited to the ascending aorta (p = 0.62). Multivariate analysis did not reveal significant risk factors for operative mortality. Postoperatively, 5 patients (8.1%) had a new postoperative cerebral vascular accident (CVA). Multivariate analysis showed an earlier date of operation as the only independent determinant for a new postoperative CVA (p = 0.0162, RR = 0.80/year, 95% CI = 0.67 to 0.96). None of the patients, operated on with antegrade selective cerebral perfusion, had a new cerebral deficit. Comparing the different methods of cerebral protection, multivariate risk analysis revealed antegrade selective cerebral perfusion as a significant protective factor against new postoperative CVA (p = 0.0110, OR = 0.12, 95% CI = 0.02 to 0.61). Survival at 5 and 10 years was 66.6.5% and 40.0%, respectively, after replacement of the aortic arch versus 68.7% and 57.7%, respectively, after replacement of the ascending aorta (p = 0.96). Freedom from aortic arch reoperation was 96.3% at 5 and 77.0% at 10 years versus 86.6% and 75.1% in both groups, respectively (p = 0.21). CONCLUSIONS: Extended replacement into the aortic arch during surgery for acute type A dissection does not influence early and late results. The best cerebral protection seems to be obtained with antegrade selective cerebral perfusion.

Operative risk factors of type A aortic dissection: analysis of 252 consecutive patients.

OBJECTIVE: We examined operative risk factors for postoperative death after surgery for acute type A aortic dissection. METHODS: Between 1974 and 1999, 252 patients, 163 men and 89 women (mean+/-SD age, 58+/-12 years) underwent surgery for acute type A aortic dissection. Fifty-eight (23.0%) were in cardiogenic shock at time of surgery. Most patients underwent ascending aorta replacement which was combined with aortic valve replacement by means of a composite graft in 30 (11.9%) patients and an isolated aortic valve replacement in 16 (6.3%) patients. RESULTS: The overall operative mortality rate was 25.0% (n=63); 27.0% for patients operated upon with aortic cross-clamping, 23.7% after deep hypotherm circulatory arrest and 23.3% after antegrade selective cerebral perfusion (ASCP) (p=0.73). Multivariate analysis revealed iatrogenic dissection (p=0.0096, odds ratio=5.7), preoperative cardiopulmonary resuscitation (p=0.0095, odds ratio=5.5) and every quarter of an hour longer extracorporeal circulation (p=0.049, odds ratio=1.1) as independent risk factors for operative mortality. Aortic valve replacement or Bentall procedure (p=0.0185, odds ratio=0.3) were protective factors. There were 44 new postoperative strokes: 4.7% in the group operated upon with and 20.1% in the group without ASCP (p=0.01). CONCLUSION: In order to avoid cardiogenic shock and preoperative cardiopulmonary resuscitation, patients with acute type A aortic dissection should be treated promptly. The choice to use an aortic valve prosthesis or Bentall procedure when applicable seems to benefit the postoperative early survival. The risk of new postoperative neurological events might be reduced by avoiding the appliance of an aortic cross-clamp and by using ASCP.